1. Field of the Invention
The present invention relates generally to a method for aligning a vehicle suspension. More particularly, the present invention relates to a method for compensating caster alignment settings to compensate for variations in camber angles.
2. Disclosure Information
When a motor vehicle is manufactured, one of the final steps in the assembly process includes the alignment of the road wheels of the vehicle. The proper alignment of the road wheels is necessary to ensure proper driving characteristics as well as optimal tire wear. One such driving characteristic is drift or pull, which refers to tendency of a vehicle to deviate from a straight line. A vehicle described as having poor drift or pull characteristics means that the vehicle is likely to deviate from the intended straight course of travel. This may be influenced by such external factors as cross winds or crowned roads, in addition to many other factors.
The adjustable alignment parameters usually associated with the steerable wheels of the vehicle, usually found at the front of the vehicle, include camber, caster and toe angles. A camber angle refers to an angle formed between an axis coincident with a wheel centerline and a vertical axis passing through a center of the road wheel, when viewed from the front. The camber angle is positive when the wheel center line at the top of the road wheel is outboard of the vertical axis. A caster angle refers to an angle formed between an axis passing through upper and lower ball joints (defining the steering axis) and the vertical axis passing through the center of the road wheel, when viewed from the side. The caster angle is positive when the axis passing through the ball joints is rearward of the vertical axis. A toe angle refers to an angle between the axis coincident with the wheel centerline and a longitudinal axis passing through the center of the road wheel, when viewed from above. The toe angle is referred to as toe-in when the wheel center line at the front of the road wheel is inboard of the longitudinal axis, and toe-out when it is outboard of the longitudinal axis.
Conventionally, an operator adjusts the camber, caster and toe angles so that they fall within a predetermined range of values determined to provide desirable driving characteristics. Making the individual adjustments consumes considerable time and effort as well as requiring specialized tooling to allow the adjustments to be made as quickly and accurately. Therefore, it would be desirable to reduce the number of adjustments an operator must make during the final alignment of the vehicle road wheels.